It is well known that in certain cardiac and renal conditions, particularly when associated with edema, hypertension, arteriosclerosis, pregnancy complications and epilepsy, the diet must be relatively salt free to avoid further damage and to ameliorate these conditions to the degree that control of diet can do. It is further known that the deleterious action of common table salt is due to sodium content thereof, since it is the sodium in the form of sodium ions, which must be avoided. Further, the tendency of the sodium content in the diet to cause an accumulation of fluids with a corresponding increase in the weight of the body tissues has underscored the importance of reducing the sodium intake in diets.
It is also known that potassium salt, a mineral present in many fruits, vegetables and legumes, protects against high blood pressure. Presence of potassium in low sodium salt inhibits sodium-induced hypertension. Reference may be made to “The Heinz Handbook of Nutrition” by Benzamin T Burton, published for H J Heinz co., by McGrew Hill Book Co. Second Edition , Page 132–133, wherein, it is mentioned that the dietary need for potassium roughly equals to that of sodium.
Salt is an excellent transporter for the supply of any nutrient supplement including potassium and micronutrients such as magnesium, calcium, zinc, iron and copper since people are consuming salt daily to improve the taste of food, though in a very limited quantity; an important example being fortification of salt with iodine and iron for the control of goiter and anemia respectively (M G Venkatesh Mannar, S Jaipal and C S Pandya, Proceedings of sixth international congress, Seoul, 1989)
Many attempts have been made to provide salty tasting compositions as a substitute for table salt, which would give similar seasoning effect, and which is comprised of substantially reduced quantities of sodium chloride.
In the fields of chemical technology, the recovery of low sodium salt from bittern, a by-product of salt industry, has gained importance because of its requirement for the patients suffering from heart problem and blood pressure and also for its nutritive value. Most typically, the pure salts are mixed together to produce low sodium salt but the prior art has also revealed that it is possible to directly produce low sodium salt by a process that involves chemical treatment of bittern with CaCl2 to separate sulfate; concentrating bittern to produce mixture of salt and carnallite and finally processing the mixture to produce low sodium salt.
Reference may be made to Biale and Zolotov, (EP0809942, dated Mar. 12, 1997 and U.S. Pat. No. 5,853,792; 29 Dec. 1998), entitled “Low sodium edible salt mixture” and “Low sodium edible salt composition and process for its preparation”, respectively, wherein composition of low sodium edible salt is described which comprises, based on dry weight of ingredients, 0–50% sodium chloride, 45–99.5% potassium chloride and at least 0.5% a additives, which comprise at least one edible nucleotide monophosphate salt and at least one member other than said nucleotide monophosphate salt selected from the group consisting of low organic acid, low organic acid salt, phosphoric acid, phosphate salt, a magnesium salt, sugar and burnt sugar. The additives have the effect of countering the bitter taste of potassium chloride. However, the drawback of this process is that the product is obtained by simple physical mixing of the ingredients and hence difficult to get a homogenous mixture.
Reference may be made to the patent of Rood Robert P. and Tilkian Sarko M. (WO8500958, 14 Mar. 1985, U.S. Pat. No. 4,473,595 dated 25 Sep. 1984)), entitled “Low sodium salt substitute” wherein a process for low sodium composition is described as a substitute for common table salt and as a magnesium dietary supplement comprised of about 40–50% of sodium chloride, 25–35% of potassium chloride and 15–25% of magnesium salt including magnesium sulfate and magnesium chloride. Presence of magnesium overcomes potassium-generated bitterness or aftertaste while providing desirable magnesium dietary supplementation. However, the drawback of this process is that the product is obtained by simple physical mixing of the ingredients and hence difficult to obtain a true homogeneous solid mixture.
Reference may be made to Vohra et al (WO 03064323 dated 7 Aug. 2003) entitled “A process for recovery of low sodium salt from bittern” who disclosed the preparation of a mixture of sodium chloride and potassium chloride containing other nutrients such as magnesium and calcium by a natural process from brine/bittern, which is a by product of salt industry. The main drawback of this process is that the salt does not contain essential micronutrients such as iodine, zinc, copper, iron and manganese.
Reference may be made to Alves de Lima et al. in patent No. BR 9806380 A, 12 Sep. 2000, entitled “Production of dietetic salt by mixing”, wherein it is stated that low sodium dietetic salt is produced by mixing sea salt with potassium chloride, potassium iodate and sodium aluminium silicate, thereby mixing 4 parts of sodium chloride with 6 parts of potassium chloride. The drawback of this process is that one has to separately procure sodium chloride and potassium chloride and blend them together in different proportion in order to obtain low sodium salt of different sodium chloride: potassium chloride ratio, so as to make a solid mixture. With this method, it is difficult to prepare a truly solid homogeneous mixture. Moreover, in this patent, no mention is made about the free flowing characteristics of the product and presence of important micronutrients required for metabolic processes.
Reference may be made to Shuqing Wang in patent No. CN 1271541A, November 2000, entitled “Multi-element low sodium nutritive salt”, who disclosed the preparation of low sodium nutritive salt by crystallizing salt from saturated brine under vacuum. The salt is then mixed uniformly with salts such as potassium chloride and MgSO4.7H2O, followed by mixing with KlO3 and Na2SeO3 solutions, drying and finally mixing with active Ca and Zn lactate. The drawback of this process is that apart from the difficulty of mixing various constituents in a homogeneous solid mixture, salt is to be crystallized from hot saturated brine involving high energy consumption thereby increasing the cost of production.
Reference may be made to DuBois et al, (March, 1992) in U.S. Pat. No. 5,098,723 entitled “Low sodium salt composition and method of preparing”, wherein, low sodium salt composition and method for its preparation is given. Here, sodium chloride is combined with a non-gritty bulking agent, and optionally a binder, to form a salt composition suitable for sprinkling onto prepared foods. This provided a composition with a salty flavor with the delivery of less sodium. The drawback of this process is that additives reduce sodium content and not by increasing potassium chloride content which is required to reduce sodium-induced hypertension.
Reference may be made to U.S. Pat. No. 2,471,144 issued to Davy E D (1949), entitled “salt substitute”, where in, a sodium free preparation containing chlorides of potassium and ammonium as the primary saline constituents (70-95% of the total ingredients) with the addition of small amount of calcium and magnesium cations and phosphate and citrate anions is proposed as a salt substitute. These ions are included in the preparation to smooth out the taste to make the preparation taste similar to that of sodium chloride. The drawback of this process is that the product is obtained by mixing the ingredients physically and hence difficult to obtain truly homogeneous mixture.
Reference may be made to Chinese patents by Zheng Haibin (CN1358456 dated 17 Jul. 2002) and Zheng Haibin & Yue Jing (CN1387794 dated Jan. 1, 2003) entitled “Health care table salt” and “Health table salt” respectively. The first patent describes edible health salts which are prepared by mixing sodium chloride, calcium carbonate, sodium selenite, magnesium sulfate and potassium iodate with several trace elements. This product possesses obvious health care effect. The latter patent describes the product which is prepared by mixing sodium chloride, various amino acids, peptide substances, vitamin B family, polysaccharide, antioxidant, nucleic acid seasoning, potassium chloride, magnesium salt, selenium salt and potassium iodide. This product effectively prevents various diseases. However, the drawback of this process is the product is obtained by simple physical mixing of the ingredients which does not give a truly solid homogeneous mixture. Moreover, the claimed product is not a low sodium salt and does not contain essential micronutrients.
Reference may be made to Korean, Japanese and US patents by Kim Won-Dae entitled “Vegetable salt preparation method” (KR 2001083036 dated 31 Aug. 2001, JP2001292725 and US2001021408) in which a method for the preparation of vegetable salt containing high mineral content and low heavy metal content is described. To obtain this, halophilic plants such as Salicornia europaea, Suaeda japonica, Suaeda maritime and Aster tripolium are used, which are subjected to hydrothermal extraction. The extractb obtained is dried and sequentially passed through ashing at 150–250° C. for 30 min, at 500° C. for 2 h and at 700° C. for more than 2 h, pulverized to obtain salt granules. The main drawback of this process is that whole plant is used for the preparation of salt. Moreover, its process is uneconomical due to hydrothermal extraction and ashing of the biomass at 700° C. Also the product described is not a low sodium salt.
Reference may be made to Ghosh et al, WO03079817 dated 2 Oct. 2003 and US2003185954 dated 2 Oct. 2003) entitled “Preparation of nutrient rich salt from plant origin” and (US2003185955 dated Oct. 2, 2003) entitled “Nutritious salt formulations of plant origin and process for the preparation thereof”, wherein, the preparation of nutrient rich salt from high salt accumulating and edible oil-bearing salt tolerant plant, Salicornia brachiata, is described in a way that allows simultaneous recovery of both salt and oil. By regularly irrigating the plants with seawater and occasionally with seawater enriched with salt bitterns and/or other types of waste/by-products containing essential nutrients, level of such nutrients in the salt is also raised. However, the salt obtained through this process is in the range of 1 to 20% of potassium chloride and is in the strict sense not a low sodium salt of adequate therapeutic value.
Reference may be made to two Korean patents by Im John Hwan entitled “Production of seaweed salt” (KR2003024737 dated 26 Mar. 2003) and Choi Byung Soo entitled “Method for manufacturing tasty salt by brown seaweeds (sea tangle)” (KR2002062878 dated 31 Jul. 2002) in which seaweeds are used for manufacturing salt. However, the product claimed is obtained from brown algae and is not a low sodium salt of medicinal value.
Reference may be made to Wu Xixin (CN1217196 dated 26 May 1999 entitled “Edible salt substitute for treating kidney disease”, wherein, preparation of sodium free or low sodium, edible salt substitute is described for curing kidney disease. This is made up by using Chinese medicinal materials and chemical salt through the process of extraction and refining. The drawback of this process is that plant materials are mixed with chemically derived salt so as to obtain desired product and hence can not be considered a product entirely of vegetable origin.
Reference may be made to a Japanese patent by Okabe Mitsutoshi entitled “Production of vegetable/alga salt” (JP10327799 dated 15 Dec. 1998), where in a process has been provided for the production of salt, effective for decreasing the amount of salt necessary for salting and capable of combining the palatability such as the flavor and the saltiness with the source of deliciousness by combining the salting preservation potency of table salt with the antiseptic preservation potency of vegetables, beneficial plants, seaweeds and grasses. The drawback of this process is that components from vegetable origin are mixed with table salt to obtain the desired product, which may not give truly homogeneous solid mixture.
Reference may be made to a Japanese patent by Yamahara Joji (JP2000004823 dated 11Jan. 2000) entitled “Plant derived mineral salt” wherein, a process has been described to obtain an inexpensive plant-derived mineral salt by ashing an ash-rich plant followed by subjecting the resultant ash to extraction with seawater and/or seawater-derived aqueous solvent at pH 6–8. The ash-rich plant used is pref. Shorea robusta, red algae or brown algae. In the above process, the liquid extract as a result of extraction with seawater is subjected to fiitration followed by concentration under reduced pressures and then boiling down to afford the objective product, which contains mineral salts such as of magnesium other than potassium at several hundred times as compared to ordinary commercial common salt, but is half the sodium content of the common salt. However, the drawback of this process is that seawater with defined pH is used for the extraction and concentration is done under reduced pressure which makes the process uneconomical. Moreover, the plant is used entirely for recovery of salt which may not turn out to be economically attractive.
Reference may be made to a Japanese Patent of Setsuko (JP10136932 dated 26 May 1998) entitled “Health Salt” where in a process for the preparation of health salt is described in which natural salt and burnt seaweed salt are the main ingredients which are supplemented with small quantity of citric acid, maltose, cane sugar or sucrose and enzymes like maltase and invertase. The salt is recovered from the solution after ionization of mineral components using strong magnetic field. The drawback of this process is that the product is obtained by mixing table salt with seaweed ash. This may not give truly homogeneous solid mixture. Moreover, recovery of salt is done using strong magnetic field for ionization of mineral components which makes the process uneconomical.
Reference may be made to a Japanese patent by Hiroshima Nobuki entitled “Table salt containing vegetable powder and vitamin C” (JP10295319 dated 10 Nov. 1998) in which the taste of table salt is improved by mixing an adequate amount of vegetable powder of natural acerola, a rose hip, a powdered green tea or a mugwort and vitamin C from citrus fruit like sour orange or a lemon. The amount of mixed powder is preferably 0.05 g based on 1 kg of table salt. However, the claimed product is a mixture of table salt and vegetable powder. Thus this product is not derived entirely from vegetable source. Moreover, the said product is not a low sodium salt.
Reference may be made to the red seaweed, Eucheuma striatum (more popularly known as Eucheuma) which is known as a source of κ-carrageenan. Eucheuma preparation is also used as foliar spray for improving flowering and growth of crops and also as edible seaweed by the name of Tosaka nori (V J Chapman and D J Chapman in their book, “Seaweeds and their uses”, Chapman and Hall, London and New York, 1980, Chapter 2, pp 30–61). Reference may also be made to the article by H. J. Bixler entitled “Recent Developments in manufacturing and marketing carrageenan” in Hydrobiologia, 326/327, 35–57, 1996, wherein it is mentioned that “there is a long history of southeast Asians eating unprocessed Eucheuma without any epidemiological evidence of health problems”.
Reference may be made to Q. Hurado-Ponce (Botanica Marina 38, 137, 1995) who has reported that Eucheuma striatum was harvested, washed and sun/oven dried for recovery of carrageenan. No reference is made to recover the adhering salt from the dried seaweed as a source of potassium chloride.
Reference may be made to K Eswaran et al entitled “Method for production of carrageenan and liquid fertilizer from fresh seaweeds” (U.S. application Ser. No. 10/222,977; International Patent No. PCT/IB 02/04112, International filing date: Oct. 8, 2002) in which an integrated method is developed to utilize fresh biomass of Eucheuma striatum to a maximum extent, for the recovery of liquid fertilizer (sap) by crushing the weeds while the residue is a superior raw material for the extraction of κ-carrageenan. Though it is mentioned that the plant sap is rich in potassium and that as-dried weed has high potassium chloride content useful as potassic manure, no attempt was made to utilize the potassium chloride for preparation of low sodium salt.